Prokaryotes, Eubacteria, Archaea, and Bacterial Genetics Vocabulary

Vocabulary flashcards covering prokaryotic structure, classification, metabolism, genetics, and ecological roles based on the provided lecture notes.

Prokaryotes

Single-celled organisms that are the oldest life forms on Earth, ranging in size from $0.1-10\,\mu\text{M}$, possessing a singular DNA strand not encased in a nuclear membrane and lacking typical eukaryotic organelles.

Domain Eubacteria

The largest prokaryotic group, characterized by cell walls containing peptidoglycan, the potential for endospore formation, and classification based on metabolism, Gram staining, and shape.

Domain Archaea

Prokaryotes that share traits with both bacteria and eukaryotes, distinguished by the absence of peptidoglycan in their cell walls.

Coccus

A sphere- or round-shaped bacterial cell.

Bacillus

A rod-shaped bacterial cell, such as Ecoli found in intestines.

Spirillum

A spiral-shaped bacterium, an example of which is Syphillis.

Filamentous

A chain of bacterial cells working and communicating together, commonly found in cyanobacteria like Anabaena and Oscillatoria.

Strepto-

A bacterial growth arrangement characterized by long chains.

Staph-

A bacterial growth arrangement characterized by bunches.

Peptidoglycan

A unique compound in bacterial cell walls that maintains shape, provides protection, and prevents the cell from bursting.

Capsule

A polysaccharide or protein layer that covers many prokaryotes.

Fimbriae

Structures found on some prokaryotes used for attachment, also known as attachment pili.

Sex Pili

Structures on bacteria used to exchange DNA.

Gram-positive

Bacteria with a thick peptidoglycan layer in the cell wall that holds onto the purple/blue crystal violet stain and is difficult to decolorize.

Gram-negative

Bacteria with a thin peptidoglycan layer in the cell wall that loses crystal violet stain, takes counterstain, and is more likely to be antibiotic resistant.

Obligate Aerobes

Bacteria that require $O_2$ to live.

Obligate Anaerobes

Bacteria that are poisoned or harmed by $O_2$.

Facultative Anaerobes

Bacteria that can survive with or without $O_2$.

Chemoautotrophs

Organisms that make energy without $O_2$ using chemicals such as $H_2S$ and $NH_3$.

Photoautotrophs

Organisms that use sunlight to make energy.

Halophiles

Archaea that live in salty environments.

Methanogens

Anaerobic archaea that produce methane.

Thermophiles/Acidophiles

Archaea that grow in hot and acidic environments.

Nucleoid Region

The region within a prokaryotic cell where most of the singular chromosome genome is located.

Plasmids

Smaller, circular rings of DNA in prokaryotic cells that are separate from the main chromosome.

Binary Fusion

The rapid asexual reproduction method used by single-celled prokaryotes.

Taxis

The ability of motile bacteria to move away from or toward a stimulus.

Conjugation

A process of bacterial genetic recombination where part of a chromosome is transferred from one bacterium to a recipient through a sex pilus.

Transformation

A process of bacterial genetic recombination where a living bacterium picks up pieces of DNA released into the environment by other bacteria.

Transduction

A process of bacterial genetic recombination where DNA fragments are carried from one bacterium to another by a virus.

Decomposers

Organisms that break down matter and return nutrients to the soil.

Producers

Organisms involved in photosynthesis and $O_2$ production, such as the cyanobacteria Anabaena and Oscillatoria.

Nitrogen Fixers

Bacteria that convert atmospheric $N_2$ into accessible forms such as nitrates ($NO_2$).